Dispute erupts after Germany blocks planned rallies that aimed to drum up support for controversial Turkey referendum.

A referendum vote that could increase the powers of Turkey's president is threatening to cause a diplomatic row with Germany.

That is after Recep Tayyip Erdogan hit out at German authorities for blocking several rallies supporting him in Germany.

He accused them of carrying out what he called "Nazi practices". About 1.4 million Turkish citizens in Germany can vote in the April referendum.

The decision to cancel the events was over security concerns in Germany, but it has led to a war of words. It comes after Turkey's arrest of Deniz Yucel, a Turkish-German journalist working for Die Welt.

He has been charged with spreading "terrorist propaganda and inciting hatred".

Will the tough talk further strain relations between the NATO allies?

Presenter: Hazem Sika

Guests:

Metin Atmaca - political analyst and professor at Ankara University

Raphael Bossong - research associate with the German Institute for International and Security Affairs

Kristian Brakel - country director for the German think-tank Heinrich Boll Foundation